Link aggregation refers to aggregating multiple ports together to form a LAG. FIG. 1 shows a LAG with two ports, where a service packet may be transferred through different ports and the bandwidth is allocated averagely among the ports. Therefore, the bandwidth increases linearly.
Once the port state changes, the ports in the LAG increase or decrease accordingly, and the packet may reselect a sending port. When the packet reselects the sending port, no selection algorithm is defined clearly in the prior art, and the implementation method varies between manufacturers. Generally, the service packets are redistributed according to the current quantity of ports. Consequently, the services on all the ports are disrupted or the service packets are disordered. Some services originally not vulnerable to impact may also change the bearer port, and the services are affected excessively.